1. Field of the Invention
The present invention relates to a technique for determining a printing medium based on the surface characteristics of the printing medium.
2. Description of the Related Art
There are a variety of types of recording apparatuses for recording information, such as characters and images, on a printing medium in the form of a sheet, such as paper and a film. Among them, a type for forming text or an image on a printing medium by attaching a recording agent (color material) to the printing medium has been put to practical use. As a representative example of such a type, an inkjet recording apparatus using a recording head including a plurality of ink ejection outlets is known. Photoprinting by an inkjet recording apparatus has spread widely and a dye ink using dye that is easily dissolved in water has been widely applied to the photoprinting. However, because of the demand for the improvement in light resistance and water resistance of printed matter in recent years, the utilization of a pigment ink has been promoted. The pigment ink exists in a solvent as particles in size from tens of nanometers to several micrometers, unlike dye that exists as molecules. As described above, the particle of the pigment ink is large compared to that of the dye ink, and therefore, it is known that printed matter with a high light resistance and a high water resistance can be obtained.
As described above, the pigment ink is superior to the dye ink in the light resistance and water resistance, but there has been such a problem that the color development properties change depending on the surface characteristics of the receptive layer in a printing medium. While the dye ink dyes the particles constituting the receptive layer in a printing medium by permeating into the inside thereof, the pigment ink dyes the particles constituting the receptive layer by depositing on the surface thereof. Because of this, in the case where an image is formed on a printing medium on which small holes or cracks larger in size than the color material particle included in the pigment ink exist, the color material flows into the inside of the printing medium and the color material distribution becomes ununiform, and therefore, the color development properties are degraded.
On the other hand, in order to implement the color tone and texture supposed by a user, a plurality of kinds of printing media having different surface characteristics has begun to be used. For example, such printing media include glossy paper whose receptive layer particle diameter is on the order of nm, matte paper whose receptive layer particle diameter is about 3 μm or more, plain paper having no receptive layer, etc. In the case where printing is performed by using the pigment ink as described above, it is necessary for a user to appropriately change the printing conditions in accordance with the surface characteristics of the printing medium that the user uses, but it is very troublesome for the user to change the printing conditions each time the kind of printing medium is changed.
Because of this, conventionally, a method for automatically determining the kind of printing medium to change printing conditions in accordance with the determination results has been proposed. A method for reading a barcode or symbol formed on a printing medium in advance and a method for determining the surface asperity and ink permeability of a printing medium based on the amount of light reflected from the surface of the printing medium on which color material is placed to change printing conditions (Japanese Patent Laid-Open No. 2001-088275) are known.
Even by the conventional technique, it is possible to determine the kind of a printing medium that a user is going to use among plain paper, glossy paper, and matte paper. However, various kinds of recording media are used for forming an image. For example, in the case of so-called coated paper, such as matte paper and glossy paper, in general, a receptive layer mainly including silica or aluminum on the base material is provided, but the structure thereof differs depending on the kind of paper, such as matte paper and glossy paper. For example, the receptive layer particle diameter of the matte paper is about 3 μm when it is small, but the diameter may be about 20 μm when it is large. Further, a deposition density representing a ratio of the volume of particles included within the receptive layer to the volume of air included therein is about 35% when the deposition density is low, but the deposition density may be about 75% when it is high. FIGS. 1A and 1B are section photos of the form of the surface of matte paper and FIG. 1A shows matte paper of the kind whose receptive layer particle diameter is as small as 3 to 5 μm and whose particle deposition density is high, and FIG. 1B shows matte paper of the kind whose receptive layer particle diameter is as large as 5 to 20 μm and whose particle deposition density is low. FIG. 1C is a table summarizing the relationship between the thickness of the receptive layer, the particle diameter, and the deposition density.
As described above, there are a variety of kinds of matte paper and the small holes and cracks on the paper surface are different depending on the receptive layer particle diameter and the deposition density. Then, there has been such a problem that the density and rubfastness are affected because a ratio of the amount of color material that deposits on the paper surface to the amount of color material that flows into the inside of the receptive layer changes depending on the relationship in size between the small holes and cracks, and the color material particles included in the pigment ink.
With regard to this point, by the conventional technique, it is possible to determine a difference between the glossy paper whose receptive layer particle diameter is on the order of nm and the matte paper whose receptive layer particle diameter is on the order of μm, but it has been difficult to determine a slight difference between the kinds of matter paper and glossy paper. Because of this, it has not been possible to perform detailed printing control in accordance with a purpose, such as the improvement in density and the improvement in rubfastness, by taking into consideration the slight difference between the kinds of matter paper and glossy paper.